1. Field of the Invention
The present invention relates to a LED module packaging structure controlled by a central signal for transmitting in long distance, in particular to an improved LED module packaging structure with an IC chip.
2. Description of the Related Art
Applications of a Light Emitting Diode (LED) can be divided into the functions of displaying and lightening. Except for the self-colored LED which has been popularly used in lightening, the multi-colored and the full-colored LED fulfills the visual demand on displaying. To display various colors of lights, each full-colored LED packaging structure includes at least red (R) LED chips, green (G) LED chips, and blue (B) LED chips, thereby mixing the RGB colors for various colors of lights. Because the percentage of the RGB colors that the colors of lights require are different, the full-colored LED needs to be matched to a driving unit for precisely controlling the mix light percentage of the RGB colors.
In tradition, a full-colored LED, a limiting resistance, and a driving unit are disposed on a printed circuit. After a plurality of circuit boards are electrically connected with each other, the full-colored LED is driven via an operating power and a control signal transmitted from central control. Most of the arrayed full-colored LED shadows are utilized to change in order to form a LED display screen. Although the conventional technique of LED display screen is completed, the limiting resistance and the driving unit need to be added onto the circuit boards, which may cause the distance between the adjacent full-colored LED to be too large, so that a more exquisite image is unable to be displayed. Further, the exposed driving unit is subject to Radio Frequency Interference (RFI) and Elector Magnetic Interference (EMI) easily.
Referring to the Taiwan patent number M356232 by “LED structure having integrated driving means” is disclosed. This prior art discloses that an IC chip and a limiting resistance are packaged in the carrier while packaging the red LED chips, the green LED chips, and the blue LED chips for forming a LED structure with an IC chip and a limiting resistance. Although this prior art improves the RFI and EMI problems and makes the displayed images more exquisite, it still has difficulty in transmitting the operating power and the control signal to the LED module from the central control. That is to say, most of the LED modules are sorted on the circuit board in array. The distances between each LED module and the central control end are not quite the same. Moreover, the central control end can be disposed far away from the circuit board. Boosting the operating power may attain a long distance transmission. However, the IC chip must be operated under a certain voltage which is generally 5V. If the voltage of the external power of the LED module is higher than the operating voltage of the IC chip, the operation of the IC chip is easily affected and may be damaged. Although the IC chip can receive the normal operating voltage by disposing an IC chip with constant voltage on the external power, the process of the circuit board or the using scheme of the electrical elements is not simplified.